This invention relates generally to devices which assist an individual in rising from a seated position, and also to spring assemblies in which the force of the spring is adjustable.
Many elderly people, as well as overweight and infirm people experience considerable difficulty in rising from a seated position in a chair or other furniture piece. This has become a particular problem with the increasing use of modern designs for such furniture, which are often closer to the floor, or support an individual in a slightly reclining position. Those with weak or inferior joints and muscles, arthritis or other types of muscular or joint crippling diseases and other such infirmities experience particular difficulty in these situations. In addition, individuals of all ages who experience back ailments often have great difficulty and discomfort in rising from many types of furniture.
Such problems are also encountered by people who are required by their occupation to sit and rise with great frequency, such as office secretaries. This type of repeated sitting and rising can cause excessive wear and strain on the lower back muscles and an attendant degree of discomfort and fatigue.
A number of attempts have been made in the prior art to solve this problem. For example, Sayles U.S. Pat. No. 1,288,216, Watt U.S. Pat. No. 1,698,344, Ruby U.S. Pat. No. 2,529,034 and Stryker U.S. Pat. No. 3,158,398 all describe seats of various types which pivot in the vicinity of their front edges to assist an occupant in rising from a seated position to a standing position. In Stryker, the seat tilts forward about a horizontal axis near its front edge under the action of torsion springs which encircle hinge pins as shown in FIG. 9 of that patent. Other prior art structures are shown in Gaffney U.S. Pat. No. 3,250,569, Condon U.S. Pat. No. 3,623,767 and Andreasson U.S. Pat. No. 4,249,774, all of which include power of motor driven seats to assist an individual in rising from a seated position.
Applicant is also aware of a commercially available device called a "lifting seat" which is portable and may be placed on a chair or other furniture piece. Although the device uses a spring for providing a resilient force to assist in rising, the spring is not adjustable, and the device is only available for specific weight ranges.
In general, previous approaches to solving this problem have been somewhat complex and expensive to produce. Moreoever, previous seating assist devices have not been easily adjustable for use by individuals of different weights and have not been easily adjustable in small increments to be precisely adjustable for the weight of the person using the chair.
Accordingly, it is an object of this invention to simply and inexpensively assist an individual in rising from a seated position.
It is also an object of the invention to provide a device which is easy to manufacture and operate, and which can be used to assist individuals of greatly varying weights to rise from a seated position.
It is another object of the invention to provide a device which may be made portable and which is lightweight and comfortable to sit on.
It is a further object of the invention to provide an adjustable spring assembly wherein the resilient force of the assembly may be quickly and easily changed.
It is also an object of the invention to provide an adjustable spring assembly for a chair in which the resilient force may be changed in small increments so as to be precisely adjustable for the weight of the individual using the chair.
Additional objects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.